Effects of Zai on Cowpea Productivity (Vigna unguiculata (L.) Walp.) in a Peasant Environment Agrosystem in Digargo in Diffa’s Urban District

Purpose: Cowpea (Vigna unguiculata (L.) Walp.) is one of the most widely cultivated food crops in Niger, but Niger's agriculture remains dependent on agro-climatic and edaphic conditions. The main objective of this study is to evaluate the combined effect of zai and the number of plants per crop on cowpea growth and yield parameters.
 Methodology: Two (2) factors were studied: the zaï’s factor (A) and the number of plants per crop factor (B). The experimental design used is a total randomization device with three (3) repetitions.
 Findings: The results showed that the A2B2 treatment is characterized by the variables, good yield of pods, seeds, biomass and dry matter. A2B2 treatment had the best grain yield compared to A2B1. The average grain yield ranges from 173.3±68.1 to 1250±720 (kg/ha). However, there is no significant difference between the different treatments on the parameter of biomass.
 Unique Contribution to Theory, Practice and Policy: In this study, the best performance is obtained with two (2) plants per crop without zai techniques.